text: The enzyme, steroid 21-hydroxylase  hydroxylates steroids at the C21 position.Steroids are a group of naturally occurring and synthetically produced organic compounds, steroids all share a four ring primary structure. The enzyme catalyzes the chemical reaction in which the hydroxyl group (-OH) is added at the C21 position of the steroid biomolecule. This location is on a side chain of the D ring.
  The enzyme is a member of the cytochrome P450 superfamily of monooxygenase enzymes. The cytochrome P450 enzymes catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.
  Steroid 21-hydroxylase is essential for the biosynthesis of cortisol and aldosterone.